As noted in U.S. Pat. No. 6,713,913, drive units for operating windows, sun-roof systems and other accessories in automobiles typically comprise an electric motor. A casing of the motor, also known as a pole cover or pole “pot”, is usually mounted to a transmission housing of the drive unit, which may optionally include an integrated electronics housing. Furthermore, a separate component may be arranged between the electric motor casing and the gearing or transmission housing as a brush holder that may simultaneously serve as seal between casing and housing. The motor casing or pole cover may comprise a deep-drawn, roughly cylindrical casing having one or more flange at its open end provided with holes to accommodate screw fasteners. Internal threads may be provided in a corresponding flange of the gearing or transmission housing, into which the screw fasteners or bolts are screwed to rigidly connect the casing and housing parts with one another.